Printing processes including size reduction of graphic intelligence



Deu 14, 1965 E. w. GRII-:SHABER ETAL 3,223,526

PRINTING' PROCESSES INCLUDING SIZE REDUCTION OF GRAPHIC INTELLIGENCE Filed May 28. 1959 I8 I8 26 le 26 2 2O zo@ F G2 FIGB IG.4

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23h 28q28c 28 280 28C 28D 28 2828b INVENToRs i EMIL w. GRIEsI-IABER 29 27 DoNALD J. NEWMAN ATTORNEYS United States Patent O 3,223,526 PRINTING PROCESSES INCLUDING SIZE REDUC- TION F GRAPHIC INTELLIGENCE Emil W. Grieshaber, White Bear Township, Ramsey County, and Donald J. Newman, White Bear Lake, Minn., assignors to Minnesota Mining & Manufacturing Company, St. Paul, Minn., a corporation of Delaware Filed May 28, 1959, Ser. No. 816,640 8 Claims. (Cl. 96-46) This invention relates to the art of reducing the size of as well as to reproducing graphic intelligence, and it also relates to the production of reduced size copies of graphic originals.

Reduction in the size of graphic intelligence and the production of reduced size copies of graphic originals has historically involved the use of expensive optical and photographic equipment. The present invention involves the totally different concept of reducing the size of graphic intelligence borne by a carrier member or sheet by physically reducing the dimensions of said sheet. The practice of the invention also involves the application of this concept in the production of reduced size copies of graphic originals.

The miniaturized products of the practice of the present invention may, for example, take the form of readily tiled negative or positive transparencies characterized by their high intensity and clarity of resolution, and which are particularly Well adapted for use as slides for photographic projection. The invention contemplates uniaxial size reduction alongr either of two normal axes, as well as simultaneous biaxial size reduction, the degree of size reduction along any given axis being preselectable. While in the illusrtated form of the invention size reduction is accomplished by shrinkage brought about by the application of heat, the invention, in its broader aspects, contemplates any suitable means for eiecting shrinkage of a carrier member bearing graphic intelligence.

The invention is capable of being practiced in a variety of ways, some of which are illustrated in the accompanying drawings, but it is to be expressly understood that the drawings are for the purpose of illustration only, and are not to be construed as a deinition of the limits or scope of the invention, reference being had to the appended claims for that purpose. In the drawings accompanying and forming a part of this specification, wherein like characters of reference are employed to designate the same parts in the several views:

FIGURES 1 to 4 are fragmentary cross-sectional views on an enlarged scale illustrating one method of producing a reduced size copy of a graphic original by the practice of the invention;

FIGURES 5 to 8 are views similar to FIGURES l to 3 illustrating another method of practicing the invention to produce a reduced size copy of a graphic original and involving actual transfer of pigment from the graphic character of the original to the copy sheet;

FIGURES 9 to 13 are cross-sectional views similar to FIGURES 1 to 8 illustrating a method of producing a reduced size positive and a reduced size negative copy of a graphic original by the practice of the present invention; and

FIGURES 14 to 18 are cross-sectional views illustrating another method of producing reduced size positive and/ or negative copies of a graphic original.

Certain polymeric lms have inherent therein the characteristic that uniaxial or biaxial stretching thereof, preferably at temperatures somewhat above the second order transition temperature thereof, eiiects orientation of the film structure such that the stretched or oriented film is dimensionally stable at normal room temperatures. Un-

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less subjected to a heat setting operation following orientation, however, such oriented films, upon exposure to elevated temperatures less than the melting temperature thereof, tend to return to their original dimensions.

Practice of the present invention exploits this phenomenon. More specifically, the present invention contemplates the reduction in size of graphic intelligence simultaneously with and as a result of shrinkage of an oriented polymeric film bearing such intelligence.

The graphic intelligence to be reduced may be imparted to the carrier iilm in any suitable manner, but it must be of a character which does not separate from the carrier iilm during shrinkage. The ensuing description sets forth several means by which graphic intelligence is imparted to a shrinkable ilrn incident to the copying of such intelligence from a graphic original. Resort may be had, however, to other suitable means, such as embossing, engraving, etching, coating and the like to impart the graphic intelligence to the film.

The shrinkable carrier lm or member used in the practice of the present invention is preferably composed of a high molecular weight, thermoplastic, iilm forming, orientable synthetic linear polymeric material. Included among the synthetic polymers aforementioned are nonheat set polyesters, non-heat set polyamides, polyoletins and substituted polyolefins Some specic examples of suitable polyesters are Mylar polyethylene terephthalate, and the reaction product of ethylene glycol and terephthalic and isophthalic acid in a ratio of 9 parts of terephthalic acid to 1 part of isophthalic acid. Suitable polyoleiins are polystyrene, polyethylene, polyvinylchloride, and copolymers of vinyl acetate and vinyl chloride. Suitable substituted polyolens are Kel-F polychlorotriuoroethylene, Saran polyvinylidene chloride, Teflon polyperuoroethylene, and Lucite or Plexiglas polymethacrylate. Suitable polyamides known commercially as nylons are polyethylene caprolactam, metaxylylene adipamide, and hexamethylenediammonium sebacate.

In the preparation of the shrinkable carrier lm or sheet, the amount and the character of the orientation or stretch to which the film is subjected within the limits of the material thereof are determined by the degree and the character of the size reduction of the graphic intelligence desired to be accomplished by shrinkage of said iilm. As is well known, an orientable polymeric ilm can be uniaxially or biaxially oriented to various degrees within the limits of the material thereof, and upon subsequent heat treatment, shrinkage will occur along the axis or axes of orientation as the case may be, so long as the oriented tilm is not heat set. Thus, a uniaxially oriented tilm and the graphic intelligence borne thereby will shrink along one axis only, whereas in the case of a biaxially oriented film, heat shrinkage will take place along both axes of orientation and in accordance with the degree of orientation along said axes. Uniaxially shrunk films bearing graphic intelligence reduced along one axis only are Well adapted for use, for example, with read-out means, for example a cylindrical lens.

As aforementioned, in the practice of the present invention the graphic intelligence to be reduced in size may be imparted to the shrinkable iilm in any suitable manner. It has been found that polymeric films of the character under consideration are particularly well adapted for the making of full size copies of graphic originals, and for the subsequent shrinking of said copies to reduced size. FIGURES l to 4 of the drawing illustrate one such method in the practice of the present invention.

In FIGURE 1, the numeral 15 indicates fragmentarily and in enlarged section a graphic original comprising a carrier sheet 16 bearing graphic intelligence 17 which may take the form of a printed or other graphic character hav- Patented Dec.` l14, l9 5 ing differential absorptivity or reflectivity such that upon exposure to radiant energy a heat image is formed thereby. In surface contact with the graphic original is placed a normally dimensionally stable heat sensitive, shrinkable copy sheet 18 which, in one method of practicing the invention, takes the form of a biaxially oriented, preferably transparent polymeric film which is transmissive of radiant energy and has not been heat set. The numeral 19 indicates a schematically illustrated source of radiant energy which may take a number of forms, including incandescent 4filament lamps, electric arcs, gas Iflash lamps or 'any other suitable source.

Brief and intense irradiation of the composite graphic original 15 and copy sheet 18 causes absorption of the radiant energy by the dark colored graphic character 17 and generation of a relatively high temperature which causes a visible change, of the character of a depressed etched area, in the associated surface areas of the copy sheet 18. The etched surface area of sheet 18 is shown on an enlarged scale at 20 in FIGURE 2, and the etched area 20 is a duplicate or image of the graphic character 17.

The copy sheet 18 is then subjected to heat treatment at a temperature substantially above the second order transition temperature of the polymeric material of the sheet and below the melting point thereof. This heat treatment may, and preferably does, involve the submersion of the copy sheet in a bath of heated liquid which does not react with said sheet, and which has approximately the same density as the material of said sheet, for example silicone oil. Exposure of the film 18 to the elevated temperature of the liquid bath causes relaxation of the polymeric material of said film and both longitudinal and transverse shrinkage thereof such that said film tends to recover the dimensions it possessed prior to orientation. As a concomitant of the biaxial reduction in the area of the copy sheet 18, the etched graphic intelligence 20 is correspondingly reduced in size. Bath temperatures of from 115 to 135 C. have been found to be satisfactory for the aforementioned shrinking operation. Progressive shrinking of a roll of polymeric web bearing graphic intelligence has also proven satisfactory. In the latter case the web may -be drawn from a roll through the heated bath in a manner similar to the technique used in the development of photographic film wherein the undeveloped film is drawn through a bath of developer and is guided along a prescribed path by suitable guide rolls.

FIGURE 3 schematically illustrates the effect of heat shrinking of the etched film 18 shown in FIGURE 2 when said film is made of certain polymeric materials, for example, polystyrene. It will Ibe noted that the etched area 20 becomes a recessed area in the surface of the shrunken film and a somewhat similar depressed area 26 appears on the side of the film opposite area 20. When the film 18 is formed of certain other polymeric materials, for example, vinyls or nylons the etched area 20,` on shrinkage of the film, becomes a projection on the surface of said film and a recessed area 26 appears on the surface of the film opposite the area 20 as shown in FIGURE 4. In either case, the end product is a reduced size transparency of the original 15 which is well adapted for use, for example, as a slide for photographic projection or as a printing plate.

, With reference to the bath of heated liquid in which the film 18 is immersed to effect shrinkage thereof, the temperature must, of course, not be so high as to cause melting of the film. Within this limitation, the rate at which the shrinking proceeds increases as the temperature of the bath is increased. The reason that it is preferable to have the liquid of the bath of approximately the same density as the film to be immersed therein is so tha-t the film, rather than resisting immersion, will readily immerse in the liquid to provide amximum surface contact and heat transfer. Having the liquid of the bath and the film of the same density provides the further and below the melting point of said material.

advantage of avoiding the occurrence of stresses within the film which might arise due to the density thereof being greater or less than that of the heated liquid.

The temperature at which the heat treatment is carried out must be such as to raise the temperature of the temperature of the film 18 substantially above the second order transition temperature of the polymeric material thereof The particular temperatures used vary with the characteristics of the particular polymeric material of the film 18 and can be readily determined by anyone skilled in the art. As illustrative examples, an oil bath temperature of from to 135 C. has been found to be satisfactory for the shrinkage of 1 to 11/2 mil polystyrene and polyvinylchloride films in the practice of the present invention. On the other hand, satisfactory shrinking of such films has been carried out by other means, for example by exposure to brief, intense irradiation in a thermographic copying machine. Shrinkage has also been carried out satisfactorily in an air circulating oven in which the temperature was C., the shrinkage of a film being substantially completed after a five minute exposure. When lower oven temperature were used more time was required to complete the shrinkage operation. Film shrinkage has also been carried out satisfactorily under a heat lamp and on a hot plate. During shrinkage in other than the liquid bath, the shrinking film may be restrained from folding upon itself by disposition thereof between a pair of fiat slip members formed of material, for example Teflon unoriented polyperiiuoroethylene which is dimensionally stable under the temperature encountered.

In FIGURES 5 to 8 there is illustrated the practice of the invention involving a graphic original 15 bearing on one side of a carrier sheet 16 graphic intelligence 17 comprising a pigment and desirably a volatilizable binder. A copy sheet or film 18 similar to the copy sheet 18 of FIGURE 1 is placed in surface contact with the surface of the original 15 bearing the graphic character 17' and is subjected to brief, intense irradiation from a lamp 19 as in FIGURE 1. Differential absorption of the radiant energy results in the formation of a heat image at the character 17"which, in turn, is believed to cause softening of the surface of the film 18' in contact with the graphic character 17 and transfer of portions of the pigment to the softened surface area along with etching of said area. Where the graphic character 17 contains a volatilizable binder along with the pigment, the heat generated causes a boiling of said binder which accelerates the pigment transfer aforementioned, portions of the volatilizable binder condensing on the film 18', and pigment portions being carried over therewith and deposited on said film.

FIGURE 6 schematically illustrates the film 18' having a surface area 20' which is an exact duplicate of the graphic character 17 of the original 15. The etched area 20 has disposed thereon :and/or infused thereinto a certain amount of pigment from the graphic character 17' of original 15'. Upon heat treatment as described hereinbefore, the size reduction of the area 20 effected byl shrinkage of the film 18', produces an intensely pigmented recessed or projected surface portion 21 as shown in FIG- URE 7 or 8 depending upon the material of the film 18', as noted in the discussion in connection with FIGURES 3 and 4. The resultant product is a readily readable reduced size transparency having extremely fine detail and which is -well adapted for use asa sl-ide in photographic projection equipment or as a printing plate.

FIGURES 9 to 13b schematically illustrate the making of reduced size negative as well as positive copies of a graphic original in accordance with another method of practicing the invention. In FIGURE 9, the reference character 15a designates a graphic original, which may be similar to the original 15 of FIGURE 1, comprising a carrier sheet 16a and graphic intelligence 17a borne by said carrier sheet. The reference character 18a indicates a sheet of film similar to the film 18 of FIGURE 1, said film being coated with a radiant-energy-transmissive layer 22 of a character which becomes visibly darkened upon exposure to heat. One example of a satisfactory heat sensitive formulation for use as the layer 22 is as follows,

proportions being given in parts by weight:

Ferric stearate 192 Spiroindane 2O Ethyl cellulose 91 Triphenyl phosphate 29 Acetone 1527 The ferrie stearate is ground, with a portion of the ethyl cellulose and acetone, Iin a blall mill until a smooth dispersion is obtained. Typically, a 200 gram charge is ground for 72 hours in a one pint capacity mill two-thirds filled with glass balls. The fern'c stearate is thereby reduced to a minimum particle size, no further reduction observable on microscopie examination being obtained on further finding.

The spiroindane employed is a polyhydroxy phenol and is a polymeric reaction product of acetone and pyrogallol formed by reaction at approximately room temperature in the presence of phosphorus oxychloride catalyst, having a moderately high molecular Weight of about 900-1600, melting within approximately the range 220-230" C., and completely soluble in acetone. It is combined with the triphenyl phosphate and the remaining ethyl cellulose and acetone to form a homogeneous solution which is then mixed with the ferric stearate dispersion.

As shown in FIGURE 9 the film 18a is placed with the heat sensitive layer 22 thereof in surface contact with the side of the original a bearing the graphic intelligence 17a. The composite of the ioriginal 15a and the film 18a are then subjected to brief intense irradiation from a source 19a, with the result that the absorption of radiant energy Iby the dark colored graphic character 17a causes generation of heat therein and darkening of the portion of the heat sensitive layer 22 `in contact therewith. The resulting darkened portion of the heat sensitive layer 22 lis shown at 23 in FIGURE 10, and this darkened area is a duplicate of the graphic character 17a.

The original 15a is then removed from the coated film 18a, and a film 24, which may be the same as the film 18 of FIGURE 1, is placed in surface contact with the coated surface yof the film 18u as shown in FIGURE 10. The composite of films 18a and 24 is then subjected to brief intense irradiation from the source 19a, causing absorption of radiant energy by the darkened coating portion 2 3 and generation of heat therein sufficient to cause said darkened coating portion to become detached from the film 18a and attached to the film 24. FIGURE l1 shows the portion 23 attached to the film 24 upon removal of said film from .the film 13a. The film 24 and darkened coating portion 23 are a full size positive copy of the original 15a, and said copy may be a transparency or a darkon-light background copy depending on whether the film 24 is transparent or opaque. The removal of the darkened portion 23 from the coating 22, as shown in FIGURE 11, leaves the recessed tarea 25 Iin which the film 18a is uncoated, said area having the same shape as the removed porti-on 23.

Upon subjection fof the films 18a and 24 of FIGURE l1 to the heat treatment described in connection with the film 18 both of said films shrink to afford corresponding size reduction of the recessed area 25 and darkened portion 23 of the films 18a and 24 respectively. In addition to shrinking, the heat treatment of the film 18a causes darkening of the heat sensitive coating portions remaining thereon, so that the resulting product, shown in FIGURE 12a or 12b depending upon the material of the film 18a, is a reduced size negative transparency of the original 15a. As shown in FIGURE 13a or 13b depending upfon the material -of the film 24, the product resulting from shrinkage of the film 24 -is a reduced size positive copy of the original 15a which, if the shrunken film 24 is transparent,

is well adapted, like the negative copy of FIGURE l2, for use as a slide in photographic projection. Where the shrunken film 24 is opaque and light in color, the resulting product shown in FIGURES 13a and 13b is a readily readable reduced size dark-on-light background copy of the original 15a exhibiting `extremely fine detail.

The copending application #of Douglas L. Johnson, Serial No. 800,446, filed March 19, 1959, now abandoned, and assigned to the assignee fof the present invention, discloses and claims an oriented opaque polymeric film which is well adapted for use as the film 24 yof FIGURES 10 to 13 in the practice of the present invention. The film referred to is opaque by virtue 'of having a multiplicity of void cells therein, said film being transparentizable upon shrinkage thereof causing elimination of the voids therein. Thus, by the use of the film referred to, practice of the invention to the stage indicated in FIGURE 1l produces a full size blackJon-white copy of the original 15a which, if desired, can be readily transformed to 'a reduced size positive transparency by subjecting the same to the heat treatment aforedes'cribed. Similar results can be obtained by the use of cold stretched polymeric film Iwhich is opaque by virtue of having been :stretched at temperatures below the second order transition temperature thereof and which is both transparentizable land shrinkable by subjection to heat treatment yas aforedescribed.

Other films usable for this purpose are transparent shrinkable polymeric films which are coated on one side (the underside as the film 24 as viewed in FIGURE 1l) with an opaque layer which is either removable or transparentizable upon shrinkage of the shrinkable base film or upon exposure to heat. An example of an opaque coating removable, as by flaking off, upon shrinkage of the base film, is a soap dispersion preferably coated wet at two mils onto the base film and allowed to dry. One such dispersion has the following formula in parts by weight:

Zinc stearate 31.5 Lithium stearate 31.5 Ethocel N-22 7.0 Acctone 280.0

An example of an opaque coating transparentizable upon exposure to heat is a blush coat of micro-crystalline wax which melts to a transparent layer upon exposure to heat. Such a wax coating, which is preferably coated onto the base film wet at two mils and allowed to dry, may have the following formula in parts by weight:

Acrowax C 54.0 Ethocel N-22 5.4 Tricresyl phosphate 5 .4 Acetone 320.0

The formation of a reduced size negative copy similar to that shown in FIGURES 12a and 12b may also be made in accordance with the principles of the present invention by utilizing in place of the film 24 in FIG- URE 10 a film having disposed in a layer thereon or dispersed therein a light sensitive and heat developable composition. One such composition is a commercially available diazo compound which releases nitrogen upon exposure to light, and if promptly subjected to heat development, the released nitrogen is expandable to form bubbles which afford opa-city in the light struck areas. If, on the other hand, the light struck composition is allowed to age in the dark the released nitrogen diffuses out, and subsequent heat treatment produces no substantial effect.

FIGURES 14 to 17 schematically illustrate the formation of a reduced size negative utilizing a light sensitive, heat developable film. In AFIGURE 14, the reference character 15b designates a graphic original which may be similar to the original 15 of FIGURE 1, comprising a carrier sheet 16h and graphic intelligence 17b borne 7 thereby. The reference character 18h indicates a sheet of film which may be similar to the film 18a of FIG- URE 9, said film being coated with a radiant energy transmissive layer 22b similar to the layer 22 of FIG- URE 9. Film 181; is placed with the heat sensitive layer 22b thereof in surface contact with the side of the original b bearing the graphic intelligence 17b, and the cornposite is subjected to brief intense irradiation from a sour-ce v19b, which may be similar to source 19 of FIG- URE 1, to cause darkening of the portion of the heat sensitive layer 22b in contact with the graphic intelligence 17b. This darkened area is shown at 23b in FIGURE 15 and is a duplicate of the graphic character 17b.

The original 15b is then removed fro-rn the coated filmt 18b, and a film 29 comprising a heat shrinkable polymeric sheet 27 having a light sensitive heat developable coating 28 is placed with the coating 28 in contact with the coating 22b of the film 1811 as shown in FIGURE 15.. The composite of films 18b and 29 is then subjected to light, for example from an ultraviolet lamp 30. The darkened portion 23b of layer 22 effectively masks from the light rays of source 30 the portion of the layer 28 in con-tact therewith. The lfilm 29 is then removed from the film `18b, the light struck portions 28a and 28b ('FIG- URE 16) of layer 22b comprising a latent image. The film 29 is then subjected to a heat shrink operation as aforedescribed, the heat being effective not only to shrink the carrier sheet 27, but also being effective to develop the light struck areas 28a and 28b of the layer 22b as shown in FIGURE 17. The heat development of the light struck areas, together with the heat shrinkage of the carrier sheet 27 affords the areas 28a and 28b dense opacity and sharp definition of the boundaries between said areas and the undeveloped area 28C affording a reduced size negative copy of extremely fine detail.

If a reduced size positive transparency is desired, the film 29 shown in FIGURE 16, bearing the latent image 28e, is allowed to age in lthe dark, for example for 24 hours at 40 C., to permit diffusion away of the nitrogen released in the light struck areas 28a and 28C. The film 29 is then subjected to exposure to ultraviolet rays, for example from the lamp 30, to activate the material in the latent image area 28C. The film 29 is then promptly subjected to a heat shrink operation as aforedescri'bed, the heat being effective not only to shrink the carrier sheet 27, `but also being effective to develop the light struck area 28C to pro-duce the reduced size positive transparency shown in FIGURE 18.

Various modifications, adaptations and alterations may be made in the practice of the invention without in any manner departing from the spirit or scope of said invention, and all of such modifications, adaptations and alterations are contemplated as may come within the scope of the appended claims.

What is claimed as the invention is:

1. The process of making a grossly reduced size copy of a graphic original having differently radiationabsorptive image and background areas comprising: brietiy exposing said original while in heat-conductive surface contact with a heat shrinkable plastic copy sheet to said radiation at high intensity to induce in said original a heat-pattern corresponding to the radiationabsorptive image areas and to provide on said copy sheet a visible reproduction of the thus heated image areas; and then uniformly heating said copy sheet above the second order transition temperature but below the melting temperature of said plastic while supporting said sheet substantially free of restraint so as to permit shrinkage of said copy sheet to said reduced size.

2. The process of making la grossly reduced size copy of a graphic original having image and background areas differentially absorptive of radiant energy, comprising: briefiy exposing said original, while in heat-conductive surface contact with a heat shrinkable plastic copy sheet having bonded to a surface thereof a thin visibly heat- Ysensitive coating, to said radiant energy at an intensity Vsufficient to induce in said original a heat-pattern corresponding to the radiation-absorptive image areas and to provide in said coating a visible reproduction of the thus .heated image areas; removing the visibly changed image .areas of said coating from said copy-sheet; and then shrinking said copy-sheet to said reduced size, while producing a visible change in the remaining areas of said coating, by uniformly heating said copy-sheet above the :second order transition temperature but below the melting temperature of said plastic While supporting said sheet substantially free of restraint.

3. The process of making a grossly reduced size copy yof `a graphic original having image and background areas differentially absorptive of radiant energy, comprising: @briefly exposing said original, While in heat-conductive surface Contact with a copy-sheet having a visibly heatsensitive coating, to said radiant energy at an intensity sufficient to induce in said original a heat-pattern corresponding to the radiation-absorptive image areas and to provide in said coating a reproduction of said image areas; transferring the image areas of said coating to the surface of a heat shrinkable plastic copy sheet; and then shrinking said plastic copy-sheet to said reduced size by :uniform heating thereof at a temperature above the :second order transition temperature but below the melting temperature of said plastic while supporting said copysheet substantially free of restraint.

4. In making a grossly reduced size copy of graphic intelligence of the type having dark-colored radiationabsorptive image areas and radiation-transmissive background areas in an initially visibly heat-sensitive surface coating on a radiation-transmissive film backing, the process comprising: bn'efiy exposing the coating containing said intelligence while in surface contact With a thin heat-shrinkable plastic film copy sheet to said radiation at high intensity to induce heating of said colored image areas and transfer of portions thereof to said copy sheet; and then uniformly heating said copy sheet above the :second order transition temperature but below the melting temperature of the plastic while supporting said sheet substantially free of restraint so as to permit shrinkage of said copy sheet to said reduced size.

5. The process of making a reduced size copy of a graphic original having image and background areas differentially absorptive of radiant energy, one of said areas consisting of an ink coating, the ink of said one area comprising a pigment and a heat-volatilizable binder, said process comprising: briefly exposing said original, while in surface contact with a thin radiationtransmissive heat-shrinkable plastic film copy-sheet, to said radiation at high intensity to cause heating and offsetting of said ink to said copy-sheet with formation of a full-size reproduction of said original; and then grossly shrinking the thus treated copy-sheet by uniform heating thereof to a temperature above the second order transition temperature but below the melting temperature of said plastic while supporting said copy-sheet substantially free of restraint.

6. The process of making a grossly reduced size copy of a graphic original having image and background areas differentially transmissive of actinic light, comprising: exposing to light through said original a copy-sheet having a thin vesicular-image diazo coating on a heat shrinkable plastic film; and thereafter developing a reduced size visible reproduction of said original by uniformly heating said copy-sheet above the second order transition temperature but below the melting temperature of said plastic while supporting said copy-sheet substantially free of restraint.

7. In the manufacture of a reproduction in miniature of a graphic original, the step of subjecting a copy-sheet, comprising a heat-shrinkable plastic film having a patterned heat-sensitive thin coating capable on heating of producing a visible reproduction of said original, to

9 uniform heating at a temperature above the second order transition temperature but below the melting temperature of said plastic while supporting said lm substantially free of restraint so as to provide simultaneous development of said visible reproduction and gross shrinking of the imaged film.

8. The process of making a grossly reduced size positive transparency reproduction of a graphic original, comprising: making a full size positive reproduction, having dark image areas on a light opaque background and corresponding to said original, on a copy-sheet comprising a heat-transparentizable heat shrinkable plastic lm; and then subjecting said lm to uniform heating at a temperature above the second order transition temperature but below the melting temperature of said plastic while supporting said ilm substantially free of restraint so as to provide simultaneous transparentizing of said background and shrinking of the imaged lm.

References Cited by the Examiner UNITED STATES PATENTS 2,008,746 7/1935 Collins 134-26 2,307,846 1/1943 Miles. 2,503,758 4/ 1950 Murray. 2,503,759 4/1950 Murray. 2,533,609 12/1950 Nolan etal. 2,543,316 2/1951 Feild et al. 2,643,598 6/1953 Carroll 96-46 2,653,091 9/ 1953 Greig 96-49 2,699,113 1/ 1955 Hoover.

2,739,909 3/ 1956 Rosenthal 117-36 2,769,391 11/1956 Roshkind Z50-65.1 2,770,534 11/1956 Marx 8-2.5 2,784,456 3/ 1957 Grabenstein.

2,808,777 10/1957 Roshkind Z50-65.1 2,859,351 11/1958 Clark et a1. Z50-65.1 2,880,110 3/1959 Miller Z50-65.1 2,910,377 10/1959 Owen 2SC- 65.1 X 2,911,280 11/ 1959 Cicogna 8-2.5 2,916,622 12/1959 Nieset Z50-65.1 2,950,194 8/ 1960 Glavin 96-49 2,974,370 3/1961 Baird 101-426 3,032,414 5/1962 James et al. 96-49 3,057,999 10/ 1962 Newman et al. 250-62.1 3,103,881 9/ 1963 Greishaber 250-65 .1

FOREIGN PATENTS 8,819 3/ 1928 Australia. 203,915 11/1956 Australia. 761,075 11/ 1956 Great Britain.

OTHER REFERENCES Renfrew et al.: Industrial and Eng. Chem, vol 38, 25 No. 9, September 19,46, pp. 870-877.

NORMAN G. TORCHIN, Primary Examiner.

MILTON STERMAN, PHILIP E. MANGAN, A. LOUIS MONACELL, Examiners. 

1. THE PROCESS OF MAKING A GROSSLY REDUCED SIZE COPY OF A GRAPHIC ORIGNIAL HAVING DIFFERENTLY RADIATIONABSORPTIVE IMAGE AND BACKGROUND AREAS COMPRISING: BRIEFLY EXPOSING SAID ORIGINAL WHILE IN HEAT-CONDUCTIVE SURFACE CONTACT WITH A HEAT SHRINKABLE PLASTIC COPY SHEET TO SAID RADIATION AT HIGH INTENSITY TO INDUCE IN SAID ORIGINAL A HEAT-PATTERN CORRESPONDING TO THE RADIATIONABSORPTIVE IMAGE AREAS AND TO PROVIDE ON SAID COPY SHEET A VISIBLE REPRODUCTION OF THE THUS HEATED IMAGE AREAS; AND THEN UNIFORMLY HEATING SAID COPY SHEET ABOVE THE SECOND ORDER TRANSISTION TEMPERATURE BUT BELOW THE MELTING TEMPERATURE OF SAID PLASTIC WHILE SUPPORTING SAID SHEET SUBSTANTIALLY FREE OF RESTRAINT SO AS TO PERMIT SHRINKAGE OF SAID COPY SHEET TO SAID REDUCED SIZE.
 6. THE PROCESS OF MAKING A GROSSLY REDUCED SIZE COPY OF A GRAPHIC ORGINAL HAVING IMAGE AND BACKGROUND AREAS DIFFERENTIALLY TRANSMISSIVE OF ACTINIC LIGHT, COMPRISING: EXPOSING TO LIGHT THROUGH SAID ORIGINAL A COPY-SHEET HAVING A THIN VESICULAR-IMAGE DIAZO COATING ON A HEAT SHRINKABLE PLASTIC FILM; AND THEREAFTER DEVELOPING A REDUCED SIZE VISIBLE REPRODUCTION OF SAID ORIGINAL BY UNIFORMLY HEATING SAID COPY-SHEET ABOVE THE SECOND ORDER TRANSITION TEMPERATURE BUT BELOW THE MELTING TEMPERATURE OF SAID PLASTIC WHILE SUPPORTING SAID COPY-SHEET SUBSTANTIALLY FREE OF RESTRAINT. 